Update -- well, of course the dealer couldn't see the long cranking...left it overnight, and it started right up for them this morning...
They did run repeated pressure tests on the HPFP, which passed each time. So they say nothing they can do at this point, as it hasn't coded and won't fail the pressure test. "Just monitor it and bring it back when it starts doing the long cranks more frequently, you get a check engine light, or if it goes into limp mode"...
At least I got a squeaking hood latch fixed and some new wiper blades! And got to drive a 135 coupe as a loaner -- what a sweet little car!